I’m not a stats expert, but it seems blatantly obvious that subgroup selection could be inherently problematic because how do you choose the groups in an effective and responsible way?
I mean, just the statement
> no subgroup is inappropriate unless you know all the values of all the parameters
seems implausible and unlikely.
In the one stats class I took, we talked a lot about how selection bias was a huge concern. Why wouldn’t Subgroup selection bias also be a concern?
I just ranted to the top two commenters so I'll keep this response brief.
Say in advance which parameters and subgroups you, as a researcher, care about in terms of significance. And keep your conclusions and discussions focused on the results for those groups. Report all of the other stuff, whether p-significant, or not, as supplementary data.
Hopefully, yours is not the only study that will use your data. Don't limit future researchers to your hypotheses.
I mean, just the statement
> no subgroup is inappropriate unless you know all the values of all the parameters
seems implausible and unlikely.
In the one stats class I took, we talked a lot about how selection bias was a huge concern. Why wouldn’t Subgroup selection bias also be a concern?
I dunno, maybe I’m wrong, but I’m dubious.